It is possible with the current solutions to transmit voluminous texts and documents in digital form via telecommunication networks of the cable, DSL (Digital Subscriber Line) or BLR (Local Radio Loop) type. Furthermore, to avoid the pirating of works and confidential documents broadcast in this manner, the latter are frequently encrypted or scrambled by various well known means.
As concerns the secure distribution of texts and binary data, WO 98/05142 discloses a process and equipment for the protection of data and their secure transmission through an electronic network. The document concerns the encryption of textual data with the aid of matrices of ASCII characters generated by keys. The three key elements at the input are a PIN code (Personal Identification Number), the number of the bank account of the user and a password. These three keys initiate the generation of a matrix A and a matrix B. Matrices A and B are generated in a pseudorandom manner with the aid of an analytic function such as a logarithmic function, a trigonometric function, a square root function or the like. The distribution of characters in matrices A and B is irregular and each character is unique. Three integrity control values are calculated and incorporated in the protected stream, one of which represents the sum of the input textual data and the two others are relative to the three input key elements. The input data is transformed into a decimal value with four numbers by operations of permutation, addition, subtraction, multiplication, division and they are then divided into two values of two numbers. These two values are indexed relative to the elements of matrices A and B to form the stream of protected data. However, due to the division into two parts for the indexation, the size of the protected stream increases considerably relative to the size of the initial data. Moreover, all the protected data, as well as the three control values generated, are present in the protected data. Therefore, WO '142 does not correspond to the criteria of high security.